1. Field of the Invention
This invention relates to a novel steam-heated milk warmer that is adapted to be used with a coffee-making machine, and particularly to a device adapted to heat milk that is then added to a coffee extract made in the coffee-making machine to make cafe'-au-lait; that is, coffee with hot milk.
2. Description of the Prior Art
It is the practice in many places in the world to drink cafe'-au-lait; a beverage made by adding hot milk to the hot water extract of ground roasted coffee beans. A machine that is designed to prepare the hot coffee extract is described in U.S. Pat. No. 4,137,833 issued to R. P. Yelloz. This machine includes means for generating hot water and low pressure steam, and means for passing hot water through a quantity of coffee grounds to produce the coffee extract.
Since milk is normally kept cold, it is necessary to heat the milk before adding it to the hot coffee extract. This machine, as do other coffee-making machines, includes a means for tapping off low-pressure steam, which steam is passed directly into a quantity of milk. This method rapidly heats the milk, but it also dilutes the milk with condensate from the steam, which alters the flavor of the beverage in an undesirable way. Also this method is hazardous if the release of steam is not properly controlled. Another disadvantage is that this prior method is relatively slow because, for proper control, each quantity of milk must be separately heated by an operator who must manually tend the valve that feeds steam into the milk. Each of these disadvantages is especially undesirable when the beverage is prepared for service in a busy restaurant.